Clicking in rear of vehicle?

[TouchdownTN]

I have recently started noticing a clicking noise coming from the rear of the vehicle after parking and removing the key. Is this the air suspension doing something? (Malfunctioning?) It clicks for about 5-10 seconds then quits. Any Ideas? Thanks in advance!

[working Hummer]

It's just the air pump. It's normal.;)

[Don Flaminco]

Yup